Tool for placing a malleolar implant for partial or total ankle prosthesis

ABSTRACT

A method of implanting in a fibula a malleolar implant including a head and a shank. The method comprises the steps of creating a bore in the fibula extending from an inner face to an outer face and applying a traction force to the malleolar implant so that the shank is pulled into the bore.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.10/254,984, filed Sep. 26, 2002; which is a divisional of U.S. patentapplication Ser. No. 09/631,938, filed Aug. 3, 2000; which claimspriority from French Application Serial No. 99 10340, filed Aug. 5,1999, all herein incorporated by reference in their entirety.

BACKGROUND

1. Field of the Invention

The present invention relates to a malleolar implant for a partial ortotal prosthesis of the ankle and to an ancillary tool for placing suchan implant.

2. Description of the Related Art

It is known, for example from EP-A-0 864 304, to fit an ankle prosthesiswith a malleolar implant intended to bear against an articular surfaceat the level of the astragalus, whether it be question of a naturalsurface or of a surface of a prosthetic component. During an operationon an ankle, access to the internal articular surfaces is limited by theligamentary system which does not necessarily allow a sufficientdislocation of the joint. In particular, access to the internal surfaceof the fibular malleolus may be insufficient, which induces difficultiesin positioning the implant, particularly by impaction.

With reference to the embodiments of FIGS. 4 and 5, it is envisaged inEP-A-0 864 304 to introduce an implant from the outer face of thefibula. However, this necessarily limits the surface of the head of thisimplant, which must be less than or equal to the surface of the orificeprovided in the bone, so that it is necessarily of relatively smalldimensions with the result of substantially fragilizing the malleolus.

For the foregoing reasons, the positioning of the malleolar implants inthe known prostheses is not entirely satisfactory.

It is a particular object of the present invention to overcome thesedrawbacks by proposing a novel malleolar implant which may be positionedprecisely, even though access to the internal surface of the fibularmalleolus may be limited and whereas its articular head presentsdimensions allowing it to perform its function efficiently.

SUMMARY

In one embodiment, the invention is a method of implanting in a fibula amalleolar implant including a head and a shank. The method comprises thesteps of creating a bore in the fibula extending from an inner face toan outer face and applying a traction force to the malleolar implant sothat the shank is pulled into the bore.

In one embodiment, the invention is a method of implanting in a fibula amalleolar implant including a shank coupled to a head. The methodcomprises the step of creating a bore in the fibula extending from aninner face to an outer face. The shank and the bore are aligned. Atraction force is applied to the shank so that the shank is pulled intothe bore.

In another embodiment, the invention is a method of implanting in afibula a malleolar implant including a shank coupled to a head. Themethod comprises the steps of creating a bore in the fibula extendingfrom an inner face to an outer face and inserting a traction memberthrough an orifice in the shank. A traction force is applied to thetraction member in a direction parallel to a longitudinal axis of thebore so that the shank is pulled into the bore.

In another embodiment, the invention is a method of implanting in afibula a malleolar implant including a shank coupled to a head. Themethod comprises the steps of creating a bore in the fibula extendingfrom an inner face to an outer face and inserting a traction memberthrough an orifice in the shank. The traction member is extended throughthe bore from the inner face to the outer face. A traction force isapplied to the traction member from a location external to the outerface of the fibula so that the shank is pulled into the bore.

In another embodiment, the invention is a method of implanting amalleolar implant in a fibula. The method comprises the steps ofcreating a bore in the fibula extending from an inner face to an outerface and providing a malleolar implant having a shank coupled to a head.A traction force is applied to the implant from a location external tothe outer face of the fibula so that the shank is pulled into the bore.

While multiple embodiments are disclosed, still other embodiments of thepresent invention will become apparent to those skilled in the art fromthe following detailed description, which shows and describesillustrative embodiments of the invention. Accordingly, the drawings anddetailed description are to be regarded as illustrative in nature andnot restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be more readily understood on reading the followingdescription of an embodiment of a malleolar implant and its ancillarytool according to the invention, given solely by way of example and withreference to the accompanying drawings, in which:

FIG. 1 is a view in perspective of an implant according to theinvention.

FIG. 2 is a view in perspective of the implant of FIG. 1 duringpositioning in a fibular malleolus, shown with parts torn away.

FIG. 3 schematically shows, with parts torn away, an ancillary tool forplacing the implant of FIG. 1, in the course of use.

FIG. 4 is a view in perspective of the tool of FIG. 3, from underneath.

While the invention is amenable to various modifications and alternativeforms, specific embodiments have been shown by way of example in thedrawings and are described in detail below. The intention, however, isnot to limit the invention to the particular embodiments described. Onthe contrary, the invention is intended to cover all modifications,equivalents, and alternatives falling within the scope of the inventionas defined by the appended claims.

DETAILED DESCRIPTION

Referring now to the drawings, the implant 1 shown in FIGS. 1 and 2 isintended to be introduced in a bore 2 made in the lateral or fibularmalleolus 3. The implant 1 comprises a convex head 4, substantially inthe form of a spherical cap and of which the radius of curvature issubstantially equal to that of the outer cheek of the astragalus of theankle in question. The shank 5 of the implant 1 is provided with outerradial flanges 6 of which the outer diameter d.sub.6 is substantiallyequal to the inner diameter d.sub.2 of the bore 2.

According to the invention, two orifices 7 are provided in the shank 5and are capable of receiving a suture thread 8 or other flexible tie.When such a thread is engaged in one of the orifices 7, it is possibleto exert on the thread 8 an effort of traction T which is transmitted bythe thread 8 to the shank 5 as represented by arrow T′ in FIG. 2. Inthis way, by pulling on the thread 8, the surgeon introduces the shank 5in the bore 2 without having to exert an effort of thrust on the head 4which may be difficult to access due to the surrounding ligamentarysystem.

In other words, it suffices for the surgeon to place a thread in one ofthe orifices 7, to pass the two strands of the thread 8 in the bore 2via the inner face of the malleolus, then to pull the strands via theouter side of the malleolus. The traction on the thread 8 has the effectof introducing the shank 5 of the implant 1 in the bore 2 and ofapplying the head 4 on the bone. The effort of traction T exerted on thethread 8 may be intense and directed parallel to the longitudinal axisX.sub.2 of the bore 2, with the result that the shank is efficientlydrawn towards the inside of the bore 2. In particular, taking intoaccount the direction and intensity of the effort of traction T, thediameters d.sub.2 and d.sub.6 can be provided to be substantially equal,with the result that the shank 5 is firmly maintained in place afterhaving been positioned.

The shank 5 is provided with two bores 7 distributed along its axisX.sub.5, the bore 7 nearest the end 5 a of the shank 5 being used. Thefact that the shank 5 comprises a plurality of orifices 7 makes itpossible to use an orifice 7 relatively close to the end 5 a of theshank 5 and to avail of such an orifice including when the shank 5 iscut in order to adapt its length to the thickness e of the malleolus 3.The number of bores 7 may, of course, be increased if necessary.

The bore 2 is made via the outer face 3 a of the malleolus 3 with theaid of the ancillary tool shown in FIGS. 3 and 4. This tool 10 comprisesa spacer block 11 provided to be disposed between the tibia T and theastragalus A of an ankle to be fitted with the implant 1. The block 11comprises a substantially planar upper surface 12 intended to cooperatewith a planar surface created by resection of the distal end of thetibia. The lower surface 13 of the block 11 is formed by two planarsurfaces 13 a and 13 b inclined with respect to each other by an angle.alpha., the surfaces 13 a and 13 b being provided to bear respectivelyon corresponding surfaces created by resection of the upper face of theastragalus A.

The surface 12 of the block 11 comprises a C-shaped housing 14 intendedto receive a shim 15 of which the upper surface 16 is in contact withthe lower surface of the tibia T. The thickness E of the shim 15 shownin FIG. 3 is such that its upper surface 16 is flush with the uppersurface 12 of the block 11.

However, thicker shims may be used when the distance E′ between thelower surface of the tibia and upper surface of the astragalus isgreater than in the configuration shown in FIG. 3.

The block 11 defines a housing 17 for receiving the end 20 of asubstantially C-shaped lug 21. The end 20 is provided with a bore (notshown) which, in the configuration of FIGS. 3 and 4, is aligned with abore 18 made in the block 11 and passing downwardly through this block,i.e. connecting the surfaces 12 and 13. A screw 19 may be introduced inthis bore which is at least partially tapped, this making it possible toimmobilize the end 20 of the lug 21 inside the housing 17. In practice,the clearance made when the screw 19 is tightened allows a limitedpivoting about axis X.sub.18 of the bore 18.

At its end 22 opposite the end 20, the lug 21 supports a clamping system23 adapted to be maneuvered thanks to a knurl 24 and making it possibleto apply the malleolus 3 of the fibula P against a stop 25 formed on anextension 26 of the end 20 of the lug 21. X.sub.23 denotes thelongitudinal axis of these clamping means. The clamping means 23 arehollow, with the result that a drill 30 may be introduced up to thelevel of the outer face 3 a of the malleolus 3 in order to make the bore2 from the outside towards the inside of the malleolus 3. In this way,the surgeon may easily aim at the suitable part of the malleolus 3thanks to the clamping means 23 which also constitute a bore guide forthe drill 30.

As the lug 21 is capable of pivoting about axis X.sub.18, the positionof axis X.sub.23 is variable in pivoting about this axis X.sub.18, whichmakes it possible optimally to adjust the orientation of the bore 2 as afunction of the exact geometry of the malleolus 3. .beta. denotes themaximum angle of pivoting of the axis X.sub.23 about axis X.sub.18. Inpractice, the angle .beta. is of the order of 10.degree.

Thanks to the tool 10, a bore 2 may therefore be formed from theoutside, allowing a rapid and efficient implantation of the implant 1.

When shims 15 of thickness greater than those shown in FIG. 2 are used,they can be provided to overlap the bore 18, as the screw 19 is placedin position before positioning of the shim 15 which is effected duringoperation as a function of the distance E′.

The invention has been shown with a total ankle prosthesis, whichcorresponds to the geometry of the surfaces 12 and 13 of the block 11.However, it is also applicable to a partial ankle prosthesis, withoutmodification of the implant 1, the ancillary tool in that case beingadapted to the geometry of the anatomical articulation surfaces betweenthe tibia and the astragalus.

Various modifications and additions can be made to the exemplaryembodiments discussed without departing from the scope of the presentinvention. For example, while the embodiments described above refer toparticular features, the scope of this invention also includesembodiments having different combinations of features and embodimentsthat do not include all of the described features. Accordingly, thescope of the present invention is intended to embrace all suchalternatives, modifications, and variations as fall within the scope ofthe claims, together with all equivalents thereof.

1. A method of implanting in a fibula a malleolar implant including ahead and a shank, the method comprising the steps of: creating a bore inthe fibula extending from an inner face to an outer face; and applying atraction force to the malleolar implant so that the shank is pulled intothe bore.
 2. The method of claim 1 comprising applying the tractionforce to the shank.
 3. The method of claim 1 comprising applying thetraction force from a location external to the outer face of the fibula.4. The method of claim 1 comprising applying the traction force so thatthe head contacts an astragalus or astragalian prosthetic component whenthe shank is pulled into the bore.
 5. The method of claim 1 comprisingapplying the traction force in a direction parallel to a longitudinalaxis of the bore.
 6. The method of claim 1 comprising inserting atraction member through at least one orifice in the shank and applyingthe traction force to the traction member.
 7. The method of claim 1comprising the steps of: engaging a traction member with the malleolarimplant; and applying the traction force through the bore.
 8. The methodof claim 1 comprising selecting one of a plurality of orifices in theshank and inserting the traction member through the selected orifice. 9.The method of claim 1 comprising applying the traction force to atraction member in a direction away from the head.
 10. The method ofclaim 1 comprising applying the traction force in a direction away fromthe head and through at least one bore in the shank.
 11. The method ofclaim 1 comprising extending a flexible traction member through a borein the shank and applying the traction force to the flexible tractionmember in a direction away from the head.
 12. The method of claim 1comprising aligning the shank with the bore.
 13. The method of claim 1comprising applying a traction force to the implant so that outer radialflanges on the shank frictionally engage with the bore.
 14. The methodof claim 1 comprising creating a bore in the fibula with a diametersubstantially the same as a diameter of the shank.
 15. A method ofimplanting in a fibula a malleolar implant including a shank coupled toa head, the method comprising the steps of: creating a bore in thefibula extending from an inner face to an outer face; aligning the shankand the bore; and applying a traction force to the shank so that theshank is pulled into the bore.
 16. The method of claim 15 comprisinginserting a traction member through an orifice in the shank and applyingthe traction force to the traction member.
 17. The method of claim 15comprising inserting a flexible traction member through an orifice inthe shank and applying the traction force in a direction away from thehead and through the bore.
 18. The method of claim 15 applying thetraction force in a direction parallel to a longitudinal axis of thebore.
 19. The method of claim 15 comprising applying a traction force sothat the head contacts an astragalus or astragalian prosthetic componentwhen the shank is pulled into the bore.
 20. The method of claim 15comprising creating a bore with a diameter substantially equal to thediameter of the shank.
 21. The method of claim 15 comprising applyingthe traction force from a location external to the outer face of thefibula.
 22. A method of implanting in a fibula a malleolar implantincluding a shank coupled to a head, the method comprising the steps of:creating a bore in the fibula extending from an inner face to an outerface; inserting a traction member through an orifice in the shank; andapplying a traction force to the traction member in a direction parallelto a longitudinal axis of the bore so that the shank is pulled into thebore.
 23. The method of claim 22 comprising the steps of: extending thetraction member away from the head and through the bore; and applyingthe traction force to the traction member through the bore.
 24. Themethod of claim 22 comprising selecting one of a plurality of orificesin the shank and inserting the traction member through the selectedorifice.
 25. The method of claim 22 comprising applying the tractionforce so that the head contacts an astragalus or astragalian prostheticcomponent when the shank is pulled into the bore.
 26. The method ofclaim 22 comprising applying the traction force in a direction generallyperpendicular to an orifice in the shank.
 27. The method of claim 22comprising creating the bore with a diameter substantially equal to adiameter of the shank.
 28. The method of claim 22 comprising engaging aflexible traction member with the shank and applying the traction force.29. The method of claim 22 comprising applying the traction force from alocation external to the outer face of the fibula.
 30. A method ofimplanting in a fibula a malleolar implant including a shank coupled toa head, the method comprising the steps of: creating a bore in thefibula extending from an inner face to an outer face; inserting atraction member through an orifice in the shank; extending the tractionmember through the bore from the inner face to the outer face; andapplying a traction force to the traction member from a locationexternal to the outer face of the fibula so that the shank is pulledinto the bore.
 31. The method of claim 30 comprising applying thetraction force in a direction generally transverse to an elongated axisof the shank.
 32. The method of claim 30 comprising selecting an orificein the shank from a plurality of orifices and inserting the tractionmember through the selected orifice.
 33. The method of claim 30comprising applying the traction force so that the head contacts anastragalus or astragalian prosthetic component when the shank is pulledinto the bore.
 34. The method of claim 30 comprising applying thetraction force generally parallel to a longitudinal axis of the bore.35. A method of implanting a malleolar implant in a fibula, the methodcomprising the steps of: creating a bore in the fibula extending from aninner face to an outer face; providing a malleolar implant having ashank coupled to a head; and applying a traction force to the implantfrom a location external to the outer face of the fibula so that theshank is pulled into the bore.
 36. The method of claim 35 comprising thesteps of: inserting a traction member through an orifice in the shank;extending the traction member through the bore from the inner face tothe outer face of the fibula; and applying the traction force to thetraction member.
 37. The method of claim 35 comprising applying thetraction force in a direction generally parallel to a longitudinal axisof the bore.
 38. The method of claim 35 comprising aligning the shankwith the bore.
 39. The method of claim 35 comprising frictionallyengaging outer radial flanges on the shank with the bore.
 40. The methodof claim 35 comprising creating the bore with a diameter substantiallyequal to a diameter of the shank.
 41. The method of claim 36 comprisingselecting an orifice from a plurality of orifices and inserting thetraction member through the selected orifice.